The present invention relates to diaphragms for pressure driven pumps.
Air driven diaphragm pumps have found great utility in the pumping of materials and powders which have any one of the properties of being very non-homogeous, very viscous, very active chemically and very dirty. In view of the wide range of applications of such pumps, it is necessary to provide a wide range of construction materials which are not chemically sensitive, not easily abraded or not easily cut by the substances and mixtures passing through the pump. One group of diaphragm materials which has been found to exhibit multiple advantages in this regard are synthetic resin polymers, some of which are offered for sale under the trademark TEFLON. However, such materials also are relatively rigid and have a tendency to fail along defined distress lines under repeated flexure. Consequently, such materials have been generally felt to be economically unsuitable for use in such situations.
In the Applicant's own experience, diaphragms having a basic configuration like that of the present invention without the addition of the ribs of the present invention fail due to cracking along radial lines of the diaphragm in a pump. Thus, TEFLON diaphragms have been found to be very expensive because of both the initial cost and the short life.
Another problem associated with the relatively hard synthetic resin polymer materials is the inability of these materials to seal with surfaces which have not been machined to a smooth surface. To overcome this problem, great pressure has generally been required to achieve a seal without the use of mastic or the like. The use of mastic is often undesirable because of the harsh environment requiring the special polymer in the first place.